Conventionally, a map display device has been used which is mounted on a mobile unit such as a car, detects the present position of the vehicle using GPS or the like and displays the position on a display together with a road map. Furthermore, with the recent spread of electric vehicles and hybrid vehicles, a technique is utilized which displays a range the mobile unit can cover with the present remaining energy, or an energy supply necessary for the mobile unit to continue traveling together with the map display. For example, a map display device disclosed in Patent Document 1 calculates, when charging the battery of a driving motor, a range the mobile unit can cover after charging the battery for a plurality of periods of time considering the remaining battery life, and displays the result on a display. In addition, a vehicle control device disclosed in Patent Document 2 shows a fuel station reachable under an energy-saving driving mode to a driver, even though only one reachable fuel station remains in a normal driving mode, and controls the driving mode of the vehicle so that it can reach the fuel station the driver desires.